The CAT SMS OTP is a complimentary authentication method for an organization with users that would rather receive their OTP by SMS.

The SMS OTP is usually used as a second factor authentication. The user is usually authenticated first by means such as a fixed ID and fixed password and then the process may require additional security and an OTP is generated and sent to the user's cellular. The user then enters the received OTP to the system and proceeds with the process.

Each OTP has a validity span that can be customized by the administrator of the system. Once the time has passed, the OTP is no longer valid - even if it has not been used.